1. Field of Invention
This invention relates to a method and apparatus for stretching plastic material, and, more particularly, to a method and apparatus for stretching dough for bread or confectionery.
2. Description of Prior Art
The prior art related to the stretching of dough of this invention is disclosed in U.S. Pat. Nos. 4,692,110 and 4,631,021, both of which issued to the assignee of this applicant.
U.S. Pat. No. 4,692,110 discloses a dough-stretching apparatus whose object is to stretch a mass of supplied dough into a sheet of dough having a predetermined thickness. However, this apparatus is neither capable of making the width of the stretched sheet of dough uniform, nor of producing the stretched sheet of dough at a constant production speed.
U.S. Pat. No. 4,631,021 discloses an apparatus for producing a sheet of dough having predetermined dimensions and delivering it at a predetermined delivery rate to produce a sheet of dough having a uniform shape. However, the proposed means is based on the measurement of the weight of a mass of dough supplied in an indefinite shape before the stretching step.